Heater apparatus for use in wells



Nov. 12, 1968 w, c, TRlPLETT ET AL 3,410,347

HEATER APPARATUS FOR USE IN WELLS Filed Jan. 26, 1967 2 Sheets-Sheet 1 5 1 i 22-"? W////a/77 c. 77vp/e {:32 l 4 Wa/zer H. Braver fjZ] 32 INVENTORJ :i BY

J 3/ di 65%;.

ATTORNEY Nov. 12, 1968 w, 1 T ET AL HEATER APPARATUS FOR USE IN WELLS 2 Sheets-Sheet 2 Filed Jan. 26, 1967 Bram er INVENTORS ATTORNEY United States Patent HEATER APPARATUS FOR USE IN WELLS William C. Triplett and Walter H. Brauer, Ingleside, Tera,

assignors of one-seventh each to George R. Garrison,

Robert Hagans, John Ralston, Jr., William Fant, and

Eugene Deadman, Corpus Christi, Tex.

Filed Jan. 26, 1967, Ser. No. 611,977 6 Claims. (Cl. 166-59) ABSTRACT OF THE DISCLOSURE This invention pertains to heater apparatus for use in wells. The apparatus is particularly useful in connection with methods for solvent recovery of petroleum from wells. The heater apparatus utilizes heat energy derived from combustion of fuels to heat solvent disposed in wells, adjacent to petroleum bearing formations, prior to introduction of the solvent into the formation to remove petroleum therefrom.

Heater apparatus utilizing heat derived from radioactive isotopes, and the solvent recovery methods herein referred to, are disclosed and claimed in copending application Ser. No. 611,895, filed Jan. 26, 1967, by the same applicants and entitled, Solvent Recovery of Petroleum, filed concurrently herewith.

This type of recovery is frequently referred to as secondary recovery, in that the recovery of the petroleum products may not be made readily by conventional methods. The invention will be most useful in the production of the so-called heavy crudes, the visc-osities and solvent flows into the formation from the well, it is heated to a substantially elevated temperature whereby its solventing properties are improved so that its penetration into the formation and its dissolution of petroleum products therefrom are greatly enhanced. This apparatus provides for heating of the solvent by combustion of fuel, and the heater apparatus may be inserted and removed from the well as desired. The equipment is thus usable repeatedly in connection with additional wells.

One great problem in connection with the recovery of petroleum products from formations lying beneath the surface of the earth is that some petroleum materials do not readily flow through the porous earth formation to wells, and hence, their recovery is exceedingly diflicult. In the case of hydrocarbon materials which have good flow characteristics, the movement of the petroleum materials to a well is not a difficult problem, since these materials will readily flow to the well. But where the materials are thick and heavy and have poor flow characteristics, movement toward the well is difiicult if not impossible.

Solvent recoveries from wells have heretofore been utilized but have in most cases been inefficient and costly. The apparatus hereby provided solves many of the problems which have heretofore been encountered. For example, earlier apparatus have utilized heating of solvents at the surface, with subsequent flowing of the solvents down a well to a formation and then into the formation. But when heating is carried out in this manner, much if not all of the heat is lost by conduction to the earth before the solvent ever reaches the underground formation. Therefore, the effect of heating is largely if not totally lost and beneficiation of the process is not a result. Heaters have been provided down-the'hole in wells, but these heaters have universally been for the purpose of melting and removing obstructing formations such as paraffin deposits in and adjacent to the producing areas of wells. None of the known apparatuses have solved the problems which are overcome according to this invention.

Other objects and advantages of the invention will appear from the following detailed description of a preferred embodiment of apparatus according to the invention, reference being made to the accompanying drawings of which:

FIG. 1 is a cross-sectional view partly schematic, taken along the vertical axis of the apparatus.

FIG. 2, FIG. 3, and FIG. 4, respectively, are enlarged partial vertical cross-sectional views, showing the upper, central, and lower portions of the apparatus.

FIG. 5 is a transverse cross-sectional view taken at line 5-5 of FIG. 3.

FIG. 6 is a partial, enlarged, vertical cross-sectional view taken at line 6-6 of FIG. 4.

Referring now to the drawings in detail, and first to FIG. 1, there is shown a well or well hole 10 through the earth structure 11 extending downwardly through a petroleum-bearing formation 12. The perforations 15 enable flow of fluids from the well into the formation, or in the reverse direction from the formation into the well. Normally the flow will be outwardly from the well, solvent being introduced through the well into the formation.

A conduit or pipe 20, only the lower part of which is shown in the drawing, is disposed concentrically within the well from the surface. A packer 22 is disposed around pipe 20 and seals between the exterior of pipe 20 and interior of casing 14. A second packer 24 is disposed in the same manner spaced below packer 22. The portion of pipe 20 shown in the drawing may be considered to be a body element of the apparatus herein described, and will be connected at its upper end with additional lengths of the same or different types and sizes of pipe extending to the surface. At its lower end portion, pipe or body 20 is diametrically enlarged at 27. A flared. section 28 connects pipe section 20 to pipe section 27. Pipe or body 27 terminates downwardly at hemispherical bottom 31, which closes its lower end. A plurality of centralizer elements 32 are secured to the outer surface of body portion 27 to maintain same in a centralized position within casing 14.

Body portion 20 has extending outwardly therefrom a plurality of circularly spaced downwardly facing outlets 34, which will be described in detail in connection with another drawing figure.

The lower end of a string of pipe 37 is disposed concentrically downwardly through the body comprising elements 20, 27. An additional concentric pipe 38 is disposed concentrically through pipe 37.

A pipe 40 is disposed downwardly through casing 14 to extend sealingly through an opening of packer 22, and a pine 41 is similarly disposed downwardly through casing 14 from the surface through both packers 22 and 24 to terminate a short distance below packer 24.

Referring now to FIG. 2 of the drawings, a portion of body or pipe 20, as indicated by line 22 of FIG. 1, is shown. As is clearly shown in FIG. 2, the downwardly facing outlets 34 each include a flared body portion 45 which narrows toward its lower end. Each outlet has a tapered passage 46 which communicates at its larger upper end with the interior of body and which has a reduced outlet 47. The outlet 47 is spaced outwardly from the wall of body 20. Although six such outlets are shown in the drawings, any suitable number may be used.

A valve seat member 49 is fixed around the interior of pipe body 20, above outlets 34, and has a downwardly diverging conical seat 50. Seat member 49 is spaced outwardly around pipe 37 which extends concentrically therethrough. A ring 52 about pipe 37 above seat 49 serves as the upper retainer for helical spring 53, the lower end of which is affixed about the upper end of valve 54. Helical spring 53 is a compression spring, which acts between ring 52 and valve 54 to bias the valve toward an open, or downwardly disposed, position. Flue gas passes upward through body 20 as indicated by arrows 57, and when the gas flow is of sui'ficient volume and velocity, the gas acts against the lower surface 58 of valve 54 to move the valve upwardly sufiicient to close the valve against seat 50. When this occurs, the flue gas is discharged from nozzle outlets 34, the flap valves 47a permitting this flow, but when closed, preventing inflow from around body 20 into the body interior. Valves 47a are spring-biased to closed positions, gas pressure against the upper surfaces thereof moving the valves downwardly to open them.

Referring now to FIG. 3, which shows a central portion of the body 20, 27 structure, there is disposed within body 27 a manifold body 60 of generally cylindrical form which is held in place within body 27 by a plurality of set screws 61, or in other suitable manner. Referring also to FIG. 5 of the drawings, body 60 has an outer sleeveshaped portion 63 and an inner outwardly cylindrical portion 64. These are connected by four radially disposed integral tube formations 65 each of which has a passage 66 therethrough. The passages 66 continue inwardly through body 64 to a central chamber 68 which is conically reduced at its upper end to join passage 69, and which is conically reduced at its lower end to join passage 70. Around the foud passages 66 radially through body portion 64 and also around upwardly directed passage 69 and downwardly directed passage 70, body portion 64 is hollowed to form a chamber 72 which has upper threaded socket opening 73 and lower threaded socket opening 74. Pipe 37 is screwed into socket 73, and a continuation of pipe 37 indicated by reference number 37a is screwed at its upper end into threaded socket 74. The upper end of passage 69 is in the form of a threaded socket and pipe 38 is screwed thereinto at its lower end. The lower end of passage 70 is in the form of a threaded socket and a pipe 38a which forms a downward continuation of pipe 38 is screwed thereinto at its upper end.

The annular space between sleeve 63 and body 64 forms a flow passage downwardly through body 60 around the radial tubular members 65. This passage, which permits flow communication past body 60, is indicated in the drawing by reference numeral 78. The ports or openings 76 through the wall of body 27 may be closed if desired, there being provided threads 80 at the outer ends of passages 66 to receive threaded plugs, solid or orificed, not shown.

Referring now to FIG. 4 of the drawings, at the lower end of pipe 37a there is threadedly connected a burner support 87, which is in the form of a circular disc or ring and which fits closely within the interior of body 27. Ring 87 is supported by pipe 37a in this manner. Ring 87 has a passage 88 therethrough providing communication from the lower end of pipe 37a. Pipe 38a is centered within pipe 37a by a plurality of centralizers 89. Pipe 38a extends downwardly through pipe 37a and through passage 88 and, at its lower end, it is of the structure shown in FIG. 6 of the drawings.

Burner support ring 87 has passages 92 therethrough, two being shown but of which there may be any desired number, each passage 92 being interiorly threaded at its upper end to receive the threaded lower end of a burner tube 93. A burner 95 is supported within each burner tube by a spider support 96 held within a pa sage 92.

Lower hemispherical end 31 of body 27 is connected thereto at threaded connection 98.

Burner support ring 87 has therethrough a plurality of circularly spaced ports 101, these being disposed annularly between the burners and the central pipe 37a as shown in the drawing.

The lower end of member 38a is inwardly and outwardly conical. A body or plug of the same angle of conical taper at its lower end is disposed within the lower end of pipe 38a. Body 105 is disposed with its upper surface just below lateral outlets 106, 107. Outlets 106, 107 are spaced below burner support ring 87. Body 105 has a handling connection 109 depending from its upper surface, to which a wire line 110, or the like, is connected. The wire line 110 is shown in all of the drawing figures. Body 105 may be lowered into its receptacle at the lower end of pipe 38a and may be removed therefrom by the wire line 110. This feature enables replacement or restoration of the components of body 105.

A packing ring 112 is disposed in a circular groove spaced just below the upper end of body 105 in the cylindrical upper portion thereof. Packing ring 112 seals between body 105 and the interior of pipe 27. Body 105 has a passage 114 therethrough through which is disposed an electrical conductor 115 leading from the surface to a female electrical connection 116 disposed in the enlarged lower end of passage 114. A male electrical connector 120 is insulatingly disposed through the lower end of body 38a to be received in connector 116, which is similarly insulated therearound. An angular passage 122 has another electrical conductor 123 therethrough which is connected to conductor ring 124 disposed in a circular groove around the tapered portion of body 105. A conductor ring 127 is disposed in a circular groove around the interior of the conical portion of the lower end of body 38a, and an electrical conductor 128 is connected therewith from the exterior of the pipe 38a. Conductor rings 124, 127 are each insulated therearound as is shown in the drawmg.

Burner support ring 87 has disposed through suitable openings therethrough the conductors 128, 130, there being two sets of these as shown in the drawing, any number being provided as necessary. These conductors lead to ignitor elements 135, one being disposed above each burner 95. The conductors 115, 123 extend with wire line 110 to the surface, and energization thereof is done when it is desired to ignite fuel to be burned by the burners, or, they may be continuously energized to insure continued combustion of the fuel.

Preferably, the ignitor element include flameionization elements, of which several forms are commercially available, and which ionize the fuel-air mixture thereby enhancing the combustion and flame characteristics.

The operation of the apparatus, in one embodiment, is as follows: Solvent is introduced from the surface downwardly through pipe 39 to be discharged between packers 22, 24, and preferably at a location immediately above packer 24. The solvent rises past jet outlets 34 and outflows through pipe 40 back to the surface. At the surface a pump (not shown) is provided to pump the solvent down through pipe 41 to below packer 24. Alternatively, the solvent may be initially pumped through pipe 41 to below packer 24, pipes 39, 40 then either not being used, or they may be omitted.

When input solvent is received through pipe 39, the solvent in rising toward the lower end of pipe 40 is heated by contact with the exterior of pipe 20. In addition, when flue gas outflow as indicated by arrows 57 is sufiicient to close valve 54 against seat 50, then the flue gas is discharged outwardly and downwardly through jet nozzles 34 to bubble upwardly through the solvent and thereby efliciently heat the solvent. This preheating of the solvent is very eificient and adds to the overall efficiency of the heating. The vertical spacing between the packers 22,

24 may be made larger or smaller as desired, in order to effect the amount of preheating of solvent desired.

The flue gas discharged through jet nozzles 34 to heat the solvent outflows with the solvent through pipe 40. A part of the flue gas is condensed.

The solvent flow downwardly through pipe 41 to below packer 24 is passed in contact with the exterior of body 27 and is thereby heated. The solvent flow may be continuous or intermittent. When the solvent flow is continuous, the degree of heating of the solvent is usually not so great as when intermittent solvent flow is used. In the case of continuous solvent flow the solvent continually passes past heater body 27 to flow through perforations 15 into formation 12. When intermittent solvent flow is used, which is preferred, the solvent is held in the annular space around heater body 27 to receive heat until the desired degree of heat is attained, after which additional solvent is flowed in amount to discharge the heated solvent from around body 27 through perforations 15 into the formation.

The heated solvent may be at a very elevated temperature, for example, a temperature approaching the boiling temperature of the solvent. Solvents such as kerosene or other light petroleum oils may :be used. Since the boiling point of kerosene is in the neighborhood of 560 F., the temperature to which the solvent may be heated, when kerosene is employed as the solvent, may be any temperature not exceeding this boiling temperature. Kerosene, of course, will frequently contain lower boiling components, so the heating temperature may be any temperature such that excessive distilling off of components of the kerosene will not be encountered at the existing downhole pressure.

Pipes 37, 37a convey combustion air to burners 95. Pipes 38, 38a convey fuel to the burners. The fuel passes through nipple connections 106, 107 to the respective burners. The combustion air discharges through passage 88 to flow beneath ring 87 and upwardly through burner passages 92 around spider supports 96. A small amount of air is permitted to rise through ports 101, which are relatively small, in order that excess combustion air will rise through the flame area so that if the air drawn in by the burners is insufficient for complete combustion completion of combustion may occur through utilization of the air inflowing through passages 101.

The wire line 110 supporting plug 105 has therealong the two conductors 115, 123 which extend through passages 114, 122, and electrical current is supplied through conductors 128, 130 to the ignitors 135.

It will be noted that the heater body 20, 27 is located,

preferably, in the well at the location of formation 12, so that heating of the solvent may occur at a location adjacent to where the solvent is passed into the formation. This provides maximum efiiciency of utilization of the heat in the heated solvent, since heat losses to the surrounding earth formations do not occur in any significant amount.

The plug or body 105 may be readily removed by drawing upwardly on wire line 110. This permits repairs or replacements to the electrical conductors and the contacts at the plug.

As has been mentioned, with reference to FIGS. 3 and 5 of the drawings, the ports 76 may, if desired, be closed by screwing plugs into the threads 80. In this case, all of the fuel introduced through pipes 38, 38a will flow to the burners. When openings 76 are not plugged, a portion of the fuel will be discharged through passages 66 and ports 76 to mix with the solvent at the exterior of body 27. Orifice plugs may be screwed into threads 80 in order that the fuel outflow may be controlled. The fuel and the solvent may be the same material. While kerosene has been mentioned as a preferred fuel and solvent, other hydrocarbon materials may be substituted as will be apparent to those skilled in the art.

The entire equipment assembly may be withdrawn from a well and used again on the same or another well at a later time. This feature makes the equipment highly desirable, as heretofore known heater equipments for downthe-hole use have been irretrievable in most cases.

While preferred embodiments of the invention have been shown and described, many modifications thereof may be made by a person skilled in the art without departing from the spirit of the invention, and it is intended to protect by Letters Patent all forms of the invention falling within the scope of the following claims.

We claim:

1. Heater apparatus for use in heating fluids in wells, comprising a tubular body means closed at its lower end and having an open upper end, connection means at the upper end of said body means for connecting said body means to the lower end of a string of well pipe, normallyopen check valve means in said body means for closing said body means in response to upward fluid flow therein, normally-closed outlet means from said body means below said check valve means adapted to open in response to fluid pressure within said body means, first and second conduit means disposed vertically through said body means and downwardly past said check valve means, burner means disposed within said body means below said check valve means and spaced above the lower end of said body means, said first conduit means having a flow connection to supply fluid fuel to said burner means, said second conduit means having a flow connection to supply combustion air to said burner means, whereby fluid surrounding said body means disposed in a well is heated at the location of said body means in the well.

2. The combination of claim 1, said first conduit means including closable outlet means therefrom to the exterior of said body means disposed between said burner means and said check valve means.

3. The combination of claim 2, including first packer means disposed around said body means above said normally-closed outlet means, second packer means disposed around said body means below said normallyclosed outlet means, each said packer means being adapted to seal between the exterior of said body means and the interior of a well in which said heater apparatus is disposed, third conduit means disposed through said first and second packer means to convey solvent from the surface to below said second packer means, fourth conduit means disposed through said first packer means to convey solvent from the surface to between said first and second packer means, fifth conduit means disposed through said first packer means to convey solvent from between said first and second packer means to the surface, releasable conduit means for providing flow connection between the upper ends of said fifth and third conduit means, whereby solvent may be conveyed from the surface by said third conduit means to below said second packer means when said releasable conduit means is released, and whereby solvent may be conveyed from the surface by said fourth conduit means to between said first and second packer means and from between said first and second packer means to said releasable conduit means and thence by said third conduit means to below said second packer means when said releasable conduit means is not released, the solvent being heated above said second packer means by heat derived from flue gas resulting from combustion of fuel at said burner means and flowing upwardly through said body means, the solvent being heated below said second packer means by conduction and radiation from said body means heated by said combustion.

4. The combination of claim 3, said fourth conduit means terminating downwardly adjacent the upper side of said second packer means, said fifth conduit means terminating downwardly adjacent the lower side of said first packer means, said normally-closed outlet means from said body means comprising a plurality of passage means spaced laterally around said body means and extending outwardly and downwardly therefrom and each including biased closure means permitting outward and downward fluid flow therethrough in response to fluid pressures within said body means suflicient to overcome said closure means bias, said check valve means being biased to open position and being closed when fluid flow of said flue gases upwardly through said body means is suflicient to overcome said bias, whereby when suflicient fuel is delivered from the surface through said first conduit means for combustion at said burner means to provide said upward flue gas flow sufficient to overcome said check valve bias, said check valve is closed and said flue gases become pressured sufficiently to overcome the biases of said biased closure means and said flue gas flows outwardly and downwardly to between said first and second packer means to commingle with and heat solvent disposed between said first and second packer means in the well.

8 5. The combination of claim 4, including electrical ignitor means and flame-ionization means at the flame area adjacent each said burner means.

6. The combination of claim 5, including removable electrical connection means for providing electrical power to said ignitor means and flame-ionization means.

References Cited UNITED STATES PATENTS 2,895,555 7/1959 De Priester 16659 3,087,545 4/l963 OBrien 166-59 X 3,315,745 4/1967 Rees 16659 CHARLES E. OCONNELL, Primary Examiner.

I. A. CALVERT, Assistant Examiner. 

